Millimetre wave corrugated waveguide-horn structures are used as both single-moded and multi-moded bolometer
feeds in a number of cosmic microwave background (CMB) experiments (e.g. PLANCK, Archeops, QUaD). Such
horns tend to be employed over a relatively wide bandwidth and for single-moded horns the waveguide acts as the high
pass filter. In this paper we report on our investigation on how the waveguide details determine the exact location of the
low frequencyband edge of such corrugated horns. A sharp step-like band edge, below which there is negligible propagation,
is ideallyrequired. Furthermore anyleakage below the expected cut-off, possible in corrugated guides, could
lead to non-idealised cross-polar effects. Typically deeper corrugations are required in the waveguide filter than at the
horn aperture for wide bandwidth operation, thus necessitating a transition section over which the corrugation depth
smoothlyvaries. An electromagnetic mode matching technique and a surface im...

Future observations of cosmic microwave background (CMB) polarisation have the potential to answer some of the most fundamental questions of modern physics and cosmology, including: what physical process gave birth to the Universe we see today? What are the dark matter and dark energy that seem to constitute 95% of the energy density of the Universe? Do we need extensions to the standard model of particle physics and fundamental interactions? Is the ACDM cosmological scenario correct, or are we missing an essential piece of the puzzle? In this paper, we list the requirements for a future CMB polarisation survey addressing these scientific objectives, and discuss the design drivers of the CORE space mission proposed to ESA in answer to the "M5" call for a medium-sized mission. The rationale and options, and the methodologies used to assess the mission's performance, are of interest to other future CMB mission design studies. CORE has 19 frequency channels, distributed ...

QUaD is a bolometric CMB polarimeter sited at the South Pole, operating at frequencies of 100 and 150 GHz. In this
paper we report preliminary results fromthe first season of operation (austral winter 2005). All six CMB power spectra
are presented derived as cross spectra between the 100 and 150 GHz maps using 67 days of observation in a low foreground
region of approximately 60 deg2. These data are a small fraction of the data acquired to date. The measured
spectra are consistent with the ΛCDM cosmological model.We perform jackknife tests that indicate that the observed
signal has negligible contamination from instrumental systematics. In addition, by using a frequency jackknife we find
no evidence for foreground contamination.

QUBIC is a unique instrument that crosses the barriers between classical
imaging architectures and interferometry taking advantage from both for high
sensitivity and systematics mitigation. The scientific target is the detection of the
primordial gravitational waves imprint on the Cosmic Microwave Background
which are the proof of inflation, holy grail of modern cosmology. In this paper,
we show the latest advances in the development of the architecture and the subsystems
of the first module of this instrument to be deployed in Dome Charlie
Concordia base - Antarctica in 2015.

In this paper we report on the design and validation process for the profiled corrugated horn antennas, which feed the bolometer array of a cosmology experiment known as QUaD located at the South Pole. This is a cosmic radiation polarization project, which demands precise knowledge and control of the optical coupling to the signal in order to map the feeble E- and B0polarization mode structure. The system will operate in two millimeter wavelength bands at 100 and 150 GHz. The imaging horn array collects the incoming signal via on-axis front-end optics and a Cassegrain telescope, with a cold stop in front of the array to terminate side-lobe structure at an edge taper of -20dB. The corrugated horn design process was undertaken using in-house analytical software tools, based on modal scattering, specially developed for millimeter-wave profiled horn antennas. An important part of the instrument development was the validation of the horn design, in particular to verify low edge tap...

We evaluate the contribution of cosmic microwave background (CMB) polarization spectra to cosmological
parameter constraints. We produce cosmological parameters using high-quality CMB polarization data from
the ground-based QUaD experiment and demonstrate for the majority of parameters that there is significant
improvement on the constraints obtained from satellite CMB polarization data. We split a multi-experiment
CMB data set into temperature and polarization subsets and show that the best-fit confidence regions for the
_CDMsix-parameter cosmologicalmodel are consistent with each other, and that polarization data reduces the
confidence regions on all parameters. We provide the best limits on parameters from QUaD EE/BB polarization
data and we find best-fit parameters from the multi-experiment CMB data set using the optimal pivot scale of
kp = 0.013 Mpc-1 to be {h2Ωc, h2Ωb, H0, As, ns,Г}={0.113, 0.0224, 70.6, 2.29×10-9, 0.960, 0.086}.